zendframework/zf2 — pull request #3848 by ThaDafinser (2013-02-21 11:54:32+00:00)
Title: Update library/Zend/Db/Sql/Predicate/Predicate.php | parameter default value

Set parameter default value to null (like in Expression).
So the parameter can be skipped, if not needed.

Example:
```php
$select->where->expression('
NOT (
column1 = column2
)
',null);
````